Organismal response to global change





  • Responses can occur at nested levels:
    • individuals

Organismal response to global change





  • Responses can occur at nested levels:
    • individuals
    • populations
    • metapopulations
    • species
    • communities
    • ecosystems
    • biomes

Finishing Unit II



Confronted with a changing world, organisms can move, adjust, adapt, or die


How do the core responses inter-relate?

How do the core responses inter-relate?



Core organismal responses are not mutually exclusive and may often be combined or inter-related


Pick any two of the core responses (move, adjust, adapt, die) and think of a way in which they relate, overlap, affect, or inform each other

How do the core responses inter-relate?



Core organismal responses are not mutually exclusive and may often be combined or inter-related


Pick any two of the core responses (move, adjust, adapt, die) and think of a way in which they relate, overlap, affect, or inform each other

Failure to move can lead to extinction


Failure to move can lead to extinction


Or organisms can move but then not successfully establish.


Moving organisms may adapt or adjust to new conditions



With warming, pikas living at low elevations can avoid extinction by migrating to cooler, higher parts of the mountain.


Low-altitude pikas must adjust/adpat to cope with low oxygen of higher altitudes


Scientists found 3 genes in the mitochondria that code for proteins that help use oxygen to generate chemical energy for the body


The proteins from high-altitude pikas appear to be very efficient at this conversion, which helps explain how they thrive high up where the air is thin

Natural selection is always a moving target…



Strong natural selection can actually reduce genetic variation in a population, making it more vulnerable to future changes

Adaptation can “save” a population from extirpation


Evolutionary Rescue: When genetic adaptation allows a population to recover from effects of environmental change that would otherwise cause extirpation

Adaptation can “save” a population from extirpation


Evolutionary Rescue: When genetic adaptation allows a population to recover from effects of environmental change that would otherwise cause extirpation

A single response can be influenced by plasticity & adaptation


Breeding dates are changing for Arctic squirrels. Most of this response (>60%) is explained by phenotypic plasticity but some of the response (~10%) appears to be caused by a genetic shift

Plasticity can serve as a “bridge to the future”


A dystopian game show




I have a species and I want you to predict for me whether it will move, adapt, have a plastic response, or die over the next hundred years.


Work together to brainstorm the pieces of information you’ll need to predict how species may respond!


Gain points by matching response traits on the game board!


For each of the four core responses brainstorm what you think are the most important factors influencing the probability of that response

Loss of breeding habitat in N. America via land conversion to croplands


Loss of overwintering habitat in Mexico (<5 acres)


Climate change threatens to disrupt the monarch butterfly’s annual migration patterns via colder, wetter winters and hotter, drier summers


Beneficial insects like monarchs and other pollinators are negatively affected by the use of pesticides to control unwanted insect and plant species


Despite the fact that toxins from milkweed may in some ways protect them, monarchs of all life stages are vulnerable to predation and disease.

Species interactions ripple through biological communities